EP3538183B1 - Electronic add-on module for injection appliances - Google Patents

Description

TECHNICAL FIELD

The present invention relates to the field of medical injection devices for administering liquid substances, in particular medications or medical substances such as insulin and hormone preparations. The invention relates to a medical monitoring system with a portable electronic additional module for attaching to an injection device.

BACKGROUND

The patent application EP 2781230 describes an injection device, also known as an auto-injector, for automatically pouring out a medical substance by means of a pre-tensioned distribution or injection spring which presses a stopper into a syringe via a piston rod. Movement of the stopper causes the substance to be dispensed or dispensed through a needle at a distal end of the syringe. Optionally, the discharge spring or another energy storage element can also automatically carry out an insertion movement of the syringe relative to a housing of the device in the distal direction. The injection device further comprises a needle protection sleeve that can be displaced in a longitudinal direction between a proximal and a distal position. The needle protection sleeve is coupled to a needle protection sleeve spring as a separate drive element, which pushes the needle protection sleeve into the distal position after the substance has been dispensed, in which it laterally surrounds or shields the needle. A movable stop element as a feedback device for generating an acoustic signal after a certain amount of substance has been released is accelerated towards a stop by the needle protection sleeve spring. A second feedback device with a stop element accelerated by the release spring signals the start of substance release.

The patent application EP 2182456 describes a portable electronic additional module for placing or snapping onto an injection device and for coupling to a proximal end, in particular to a dose setting button, of the injection device. A movable contact element in the form of a ball touches a front end surface of the injection device when the additional module is in place and is coupled to a piezoelectric sensor or a pressure sensor. Axial vibrations are detected by the sensor, and characteristic operational states or processes are identified by evaluation electronics in the additional module. The additional module has a small extension in a longitudinal direction of the injection device, so that the latter is held directly by the user even when the additional module is attached.

The term “medication” or “medical substance” in this context includes any flowable medical formulation that is suitable for controlled administration using a cannula or hollow needle, for example a liquid, a solution, a gel or a fine suspension containing one or more medicinal active ingredients . A drug may therefore be a single active ingredient composition or a premixed or co-formulated multi-active ingredient composition from a single container. The term includes in particular drugs such as peptides (e.g. insulins, insulin-containing drugs, GLP-1-containing and derived or analogous preparations), proteins and hormones, biologically derived or active active ingredients, active ingredients based on hormones or genes, nutritional formulations, enzymes and other substances both in solid (suspended) or liquid form. The term also includes polysaccharides, vaccines, DNA or RNA or oligonucleotides, antibodies or parts of antibodies as well as suitable base, auxiliary and carrier materials.

PRESENTATION OF THE INVENTION

It is an object of the invention to create a simple and cost-effective way to monitor or control the correct execution of an injection process carried out with an automatic injection device and to forward the injection-relevant data. It is a further object of the invention to enable safe interaction of components, devices and systems for generating, collecting and distributing data in connection with the use of injection devices.

This task is solved with the help of an additional electronic module which, before the start of the injection, is releasably placed or plugged onto an automatic injection device with a longitudinal axis which connects a proximal end and a distal or puncture-side end of the injection device. According to the invention, the additional module comprises a force sensor for measuring a time-varying axial force component in the direction of the longitudinal axis that is exerted or transmitted by the injection device to the attached additional module during an injection process. According to the invention, the additional module comprises a handle or a preferred grip position for gripping and holding the injection device and the attached additional module, or the additional module and the inserted injection device. The handle can be a part of a module housing of the additional module that is ergonomically preformed so that it can be grasped by a hand of a user of the injection device, so that all other areas of the additional module and the injection device that are visible in the coupled state appear to a user as significantly less suitable for grasping. A user who only grips the injection device using the handle of the attached additional module cannot introduce any forces directly onto the injection device or remove them from the injection device. In particular, in static equilibrium, comparable axial forces are transmitted to the injection device at the puncture point and via the additional module, so that the force sensor in the additional module not only detects a vibration behavior of the injection device but also measures a constant or only slowly changing axial force introduction by the user that does not produce any acceleration can.

The additional module comprises a sleeve-shaped module housing with a device receptacle or opening into which the injection device is inserted before the start of the injection and which at least partially surrounds the injection device in the attached state. The handle is also part of the module housing and surrounds the device holder, and the handle also has an extension in the direction of the longitudinal axis of at least half the width of a user's hand, in particular an extension of at least five or at least eight cm. The handle is therefore provided radially outside the device holder, which leads to a more compact shape than an extension on the additional module that extends axially or laterally beyond the injection device. A clear width of the device holder is, at least in the area of the handle, slightly larger than an outer diameter of the injection device, so that even at maximum handle pressure, the device holder is not pressed onto the injection device and no friction or holding forces are created in the longitudinal direction over the device holder between the injection device and the additional module Bypassing the force sensor.

In a further preferred embodiment, the additional module has a releasable holding mechanism which, when attached, restricts or even makes movement of the additional module relative to the injection device in the direction of the longitudinal axis. By limiting the relative movement in the axial direction, the forces acting on the force sensor in the proximal direction during the injection can be limited. The holding mechanism secures the injection device and additional module against unintentional decoupling, and the force peaks acting on the additional module in the distal direction when the needle cap is removed can be diverted via the additional module.

The additional module has evaluation electronics, configured to identify processes in, or states of, the injection device during an injection process, based on measurements of the force sensor, in particular based on significant changes in the axial force caused by movements of the user or by an enabled drive mechanism. For example, the detection of an increase in the measured axial force component to a value that does not fall below a minimum holding force during a certain minimum injection time and a subsequent drop in the axial force to zero can be seen by the evaluation electronics as the effort exerted by a user between the piercing process and removal of the injection device with a corresponding movement of a needle protection sleeve including pressurization of an associated one Needle protection sleeve spring can be identified. Furthermore, superimposed movements of components of the injection device, such as turning a sleeve or deflecting a snapper for locking or unlocking, can lead to an identifiable, time-limited increase or decrease in the measured axial force.

In a further development of this advantageous variant, short-term force surges lasting a few milliseconds and resulting from automatic, spring-driven movements of a stop element of the injection device are also registered or detected to signal the start or end of distribution. The measured force impulses can, for example, decay quickly Oscillations or vibrations of the injection device relative to the additional module correspond. In particular will a start of the distribution is identified by a correlated measurement of a rapid increase in the axial force to a holding force value and a clear force surge, while an end of the distribution is identified by measuring a force surge in combination with a constant axial holding force. The signaling preferably includes an unbraked acceleration phase of the stop element and a subsequent stop or impact of the stop element to stimulate vibration in the injection device, which can be perceived primarily by the user as an acoustic or tactile click signal and can also be measured by a suitably placed axial force sensor.

In an advantageous further development, a short-term force impulse signal from the force sensor is filtered and compared in a comparator or a comparison circuit with a first and preferably a second or further threshold value and converted into a multi-valued, in particular two- or three-valued, discrete event pattern in the output signal of the comparator. If an event pattern determined in this way matches a predetermined and stored base pattern that characterizes a specific base event, the original force impulse signal is identified as belonging to the specific base event. It is therefore taken advantage of the fact that a basic event, for example a stop of a stop element for signaling a start or end of distribution, has a characteristic multi-valued basic pattern in the axial force output signal of the comparator, which is reflected in every event pattern of a one-time registered stop event.

In an alternative further development of the advantageous variant, the additional module has a microphone or acoustic sensor for measuring an acoustic signal during the injection process, in particular vibrations of the injection device transmitted through the air. In this case, the evaluation electronics identify the event based on measurements from the microphone and measurements from the force sensor. For example, a start of the distribution is identified by a correlated measurement of a rapid increase in the axial force to a holding force value and a clear acoustic signal, while an end of the distribution is determined by measuring a clear acoustic signal in combination with a constant axial holding force.

A single-axis or multi-axis acceleration sensor or a gyroscope can also be used as alternatives to the microphone. With these alternatives, as with the microphone, the placement of the sensor in the additional module is less critical compared to the force sensor, which relies on a contact surface with the injection device. In these further developments, the additional module continuously measures, on the one hand, an axial, in particular constant, minimum force of the user on the injection device, and, on the other hand, carries out a second measurement with a sensor type different from the force sensor, with the two measurements being evaluated together for event identification.

A state of the injection device or a process of an injection process can therefore be determined by the additional module solely on the basis of the measurements of the axial force sensor, optionally supplemented by measurements from a second sensor. In fact, it is a complex detection of a discontinued or released Dose is often neither possible nor necessary for a meaningful determination of the status or process. An injection process can be classified as having taken place correctly based on the three events of piercing/start of distribution, end of distribution, and device removal. If the order of these events or a period of time in between does not correspond to expectations, the additional module can generate a corresponding message.

An additional module according to the invention can advantageously be used repeatedly to monitor the use or use of automatic disposable injection devices or auto-injectors. In particular, the additional module is suitable for retrofitting existing injection devices that are not available for adaptation or modification. In this configuration, no sensors are provided in the injection device for acquiring or processing sensor data about the operation of the device, nor is there a communication interface for transmitting this data to a receiver. Accordingly, the force sensors in the additional device must be designed and positioned in such a way that they can detect changes in state or primary signals from within the injection device.

In a further embodiment of the invention, the additional module comprises a communication unit for wireless communication with a mobile device, for example a cell phone or smartphone, and/or an optical, acoustic, or tactile status indicator. A displayed state or status of the system can include a device state of the injection device, a module state of the additional module, or a process state of an ongoing or completed injection process. The status indicator can be kept simple and limited to a few LEDs, for example in traffic light colors, and/or an acoustic signal generator to generate speech-independent noises or melodies. This is particularly advantageous in conjunction with the advanced graphical display options and voice output options of a smartphone, since the smartphone, which is wirelessly coupled to the additional module, takes over the refined communication with the user that goes beyond a status display. The status information can include information about the expiration of a holding time or waiting time, which the user must wait after the delivery has been completed before the injection device can be safely removed from the injection site. A simple recording of the time that has elapsed since the end of the discharge was determined and a comparison with a target duration allows the user to see the time to safely remove the injection device. This can be done both by an additional module with a time recording function and by a mobile device coupled to the additional module with real-time event transmission.

Further embodiments and refinements can be directly and obviously recognized by the person skilled in the art, which result from combinations of the examples described or combinations of the examples described with the general specialist knowledge of the person skilled in the art.

CHARACTERS

• Fig.1 zeigt ein Injektionssystem mit einem Injektionsgerät und einem Zusatzmodul;
• Fig.2 zeigt eine Injektionsvorrichtung im Längsschnitt;
• Fig.3 zeigt eine Explosionsdarstellung eines Zusatzmoduls;
• Fig.4 zeigt gemessene Signale eines Kraftsensors und eines Mikrofons im Zusatzmodul;
• Fig.5 zeigt ein Schema für eine Auswerteelektronik eines Zusatzmoduls;
• Fig.6 zeigt ein durch einen Kraftsensor gemessenes und gefiltertes Signal;
• Fig.7 zeigt eine Ereignismusterbildung aus einem Kraftstosssignal; und
• Fig.8 zeigt ein erweitertes medizinisches Überwachungssystem.

Preferred embodiments of the invention are described below in connection with the attached figures. These are intended to show basic possibilities of the invention and are in no way intended to be interpreted in a restrictive manner.

• Fig.1 shows an injection system with an injection device and an additional module;
• Fig.2 shows an injection device in longitudinal section;
• Fig.3 shows an exploded view of an additional module;
• Fig.4 shows measured signals from a force sensor and a microphone in the additional module;
• Fig.5 shows a diagram for an evaluation electronics of an additional module;
• Fig.6 shows a signal measured and filtered by a force sensor;
• Fig.7 shows an event pattern formation from a force impulse signal; and
• Fig.8 shows an advanced medical monitoring system.

FIGURE DESCRIPTION

Fig.1 shows an injection system with an injection device 1 and an additional module 2, both in separate ( Fig.1 above) as well as in assembled or coupled ( Fig.1 below) condition. The injection device has an elongated device housing 10 which is symmetrical about a longitudinal axis, and a needle protection sleeve 11 which is located between a first position (in Fig.1 shown) and a second position that releases the needle. A needle protection cap remover 12 is mounted on a distal end of the injection device when delivered and must be removed or pulled off before the injection together with a needle protection cap that mechanically protects the needle. The additional module has an elongated, sleeve-shaped module housing 20 with a cavity as a device holder for the injection device, which is matched to an external shape of the device housing, so that the injection device can be inserted into the additional module for coupling. The additional module has a release button of a holding device 24a, an optical status display 23c, 23d for visual feedback to the user, and side openings 20a, which, when coupled, are aligned with windows 10a in the device housing and enable a view of a substance stored in the injection device . Alternatively, the additional module can also be significantly shorter than the injection device, i.e. only around two thirds or a good half as long. The module housing has a handle 21 on the outside with a slightly concave handle position, which includes a slight elevation 21a or an area with an enlarged diameter as the distal handle limit to make it easier to absorb user force in the distal direction.

At the beginning of an injection, the distal end of the injection device, i.e. the needle protection sleeve, is pressed onto the injection site by the user so that the needle protection sleeve is pushed into the injection device in the proximal direction under tension of the needle protection sleeve spring and at the same time the needle penetrates the injection site. To ensure that in any case the user has the power during the The entire injection process, including triggering and carrying out the distribution, is transferred to the injection device using an additional module, the additional module is designed as a sleeve over a large part of the injection device. This means that the injection device cannot be held unintentionally. A clear width or an inside diameter of the device holder is, at least in the area of the handle, larger than an outside diameter of the injection device by an amount of a few tenths of a millimeter that exceeds the manufacturing tolerances. The additional module has some play radially relative to the injection device so that they can move towards each other without friction and the entire force is transmitted via the force sensor.

Fig.2 shows an injection device in longitudinal section, in a state before the injection, into which a syringe 13a filled with a substance to be delivered is inserted with a needle 13b. A hollow cylindrical needle protection sleeve 11 has a proximal end in contact with a rigid locking sleeve, which in turn rests on a needle protection sleeve spring 14. At the proximal end of the needle protection sleeve spring, a first stop element or click element 15a is provided for marking an end of injection (Eol). At the beginning of the distribution, a piston rod is connected to the first stop element by means of cams, so that the first stop element can be moved forward by a small stroke at the beginning of the distribution and the needle protection sleeve spring is thereby further tensioned or compressed. After the substance has been completely released and the forward movement of the piston rod has been completed, the first stop element is released and accelerated proximally backwards by the needle protection sleeve spring, where it hits an end cap and produces a clicking noise that is clearly audible to the user and a noticeable impact. A second stop element 15b or click element is provided to mark a start of injection (sol). A click pin is initially locked to the piston rod against relative movement. When the distribution is triggered by proximal displacement of the needle protection sleeve and the locking sleeve, the piston rod and click pin are released, which are driven apart by a pre-tensioned distribution spring 16. This movement of the click pin is transmitted to the second stop element, so that the proximal end of the second stop element hits the end cap and produces a clearly audible clicking noise and a force surge or impulse.

As an alternative to the simultaneous needle protection sleeve insertion and needle insertion, a syringe that is slidably mounted in the injection device, which in the delivery state is completely enclosed by the device housing including the needle tip, can be moved relative to the device housing by the force of an insertion and/or ejection spring. This automated piercing movement is triggered after the needle protection sleeve has been partially or completely inserted into the injection device. An impact of the accelerated syringe on a stop element also causes a significant surge of force followed by an approximately constant holding or dispensing force. The previous insertion movement of the needle protection sleeve with simultaneous tensioning of the needle protection sleeve spring can take place slowly, in the case of a preloaded needle protection sleeve spring possibly only after a spring preload force has been overcome. The movement can result in a continuous increase in the measured axial force, possibly with the application of a minimum unlocking force that is visible in the force curve and superimposed on the spring compression force Injection locking force. In a further embodiment, the piercing movement can also be started by a trigger button that can be activated by the user.

Fig.3 shows an exploded view of an additional module according to the invention. The module housing includes a first housing half 20b and a second housing half 20c, which are snapped onto a module sleeve 20d. The module electronics are housed in an electronics holder 23a in the rear part of the additional module, comprising a force sensor 22 or a pressure sensor, a contact switch 23b for detecting a complete insertion of the injection device into the additional module, a connection indicator 23c for signaling a successful connection establishment with a mobile device, a Status display 23d with LEDs and light guides in the form of a transparent distal end cap. Also provided are a microphone 23e, a battery 23f as an energy source, a buzzer or loudspeaker 23g for generating noise, and a communication unit 23h with a Bluetooth Low Energy (BLE) chip including an evaluation unit for signal processing and data storage. The status display can in particular show the following states: additional module plugged in, additional module ready, injection running, injection completed, hold time expired, remove additional module, BLE status. The status display can also issue warnings such as additional module installed incorrectly, additional module switches off due to inactivity, battery level low, reminder to remove additional module, or even error messages such as injection termination during distribution, injection termination during hold time.

A holding device or a holding mechanism comprises an annular transmission element 24b guided in the module sleeve, a holding structure or nose fixedly arranged on the transmission element, a latching spring which moves the transmission element with the holding structure into a holding position, and a release button as an actuating element 24a for moving the transmission element and for release the holding structure from the holding position. In the holding position, the holding structure is snapped into a recess such as a notch or a slot in the housing of the injection device. This recess can also be used for other purposes and is ideally already present in existing injection devices, which means that no adjustment has to be made to the injection device to use the additional module. As an alternative to pressurizing the release button and moving the transmission element perpendicular to the longitudinal axis, the actuating element can also carry out a pushing movement. When the holding structure is released, the injection device can slide out of the additional module in the axial direction, so the holding mechanism allows the additional module to be releasably snapped onto the injection device. The module housing in Fig.3 differs from the one in Fig.1 , in particular due to the arrangement of the holding device within the handle area instead of between the handle area and the distal end of the housing. The holding device is therefore held by the user when holding it; in this case, the release button is slightly recessed in the module housing in order to prevent unintentional release by the user's holding hand.

By appropriately designing the holding structure and recess, the holding device can have some play in the axial direction, so that the force sensor can move away from the end cap or contact surface. In this case, there is no preload on the force sensor if the injection device is not on the Injection site is in place and the needle protection sleeve spring is not compressed. Accordingly, a signal or click at the end of the delivery may no longer be recognized by the force sensor after the injection device has been removed prematurely, so that only acoustic identification via the microphone can contribute to completing the incorrect injection process. On the other hand, the force sensor can also be preloaded or prestressed by force-fitting snapping of the holding structure of the additional module into the recess of the injection device. In this case, a prestressing section in the module housing between the holding device and the force sensor is correspondingly preloaded in tension, and under certain circumstances external axial forces can only be observed on the force sensor above a certain prestressing value. A force sensor placed on the proximal end face of the injection device initially measures the preload value as well as any small user force, which is diverted backwards, for example, bypassing the preload path. On the other hand, in the preferred arrangement of the handle as part of the module housing surrounding the device holder, part of the user's axial force is at least partially directed to the force sensor via the preload path. This first reduces the tensile load in the pre-tensioning section, and only user forces above a minimum value that does not exceed the pre-tensioning force are measured by the force sensor in addition to the pre-tensioning force.

In the embodiment shown, the axial force sensor comes to rest at the proximal, or rear, end of the injection device when the additional module is in place. It therefore touches a proximal end face or end cap of the injection device, which represents a simplification compared to force transmission via a contact surface to be provided on the side of the device perpendicular to the axis, for example via a proximal annular surface of a circumferential flange or a section thereof. It is also conceivable to redirect the axial force by means of movable components on the additional module in a direction that deviates from the longitudinal direction, for example for non-axial placement of the force sensor.

Suitable force sensors are based on a piezoresistive effect, i.e. on a change in the specific electrical resistance of a conductor when mechanically deformed. In force sensors from the FSS series from Honeywell, the resistance of piezoresistors integrated into a silicon measuring element increases when they are bent by force, which can be measured via a resistance bridge. The sensor transmits an applied force between zero and 20 Newtons directly to the silicon measuring element via a stainless steel ball, moving the ball by a maximum stroke of 50 micrometers. Alternative force sensors for measuring holding forces include strain gauges mounted on bending beams, or FSR (Force Sensing Resistor) pressure sensors.

The evaluation unit can be integrated in the communication unit 23h or provided as an independent chip on the electronics holder. The evaluation unit processes the signals from the force sensor and any other sensors provided, provides a time stamp, and determines consolidated injection information from the processed signals and the associated time stamps. The latter includes at least the information that an injection was carried out successfully at a certain point in time, or what incorrect actions may have been taken. This information is in a Storage unit stored in the additional module and/or forwarded via the communication unit. The storage unit can also store identification data of the user or the additional module.

For energy saving purposes, the contact switch 23b can also function as an activation element to activate the additional module from a power saving mode. Additionally or alternatively, the energy source can be rechargeable, for which the additional module has a suitable plug or is intended for inductive energy transmission from a charging station. The charging station can only accommodate the additional module, or the additional module with the injection device inserted, and can also be used by the user's other rechargeable devices. An intelligent charging station can function as a base station and have additional functionalities, for example temperature measurement of the inserted injection device or the medication it contains. If the injection device is placed in the charger after storage in the refrigerator and before use, such a temperature measurement on the injection device can output a signal as soon as a minimum temperature for administering the medication is reached. During this warm-up process, the power source of the additional module can also be recharged without further intervention from the user. Via a further communication interface, the intelligent charging station can also provide time and date information for synchronizing a clock of the additional module, or accept the consolidated injection information as a fallback level to the mobile device as described below.

Fig.4 shows the signals from a piezoresistive force sensor (top) and an electret microphone (bottom) measured during a complete injection process lasting 20 seconds. The following events are assigned to the signals: (a) connecting the additional module and the injection device, (b) removing the needle protection cap from the injection device, (c) moving/tilting the injection device to the injection site, (d) starting the delivery (Start of Injection, Sol), ( e) End of Injection (Eol), (f) removing the injection device from the injection site, (g) placing the injection device in a horizontal position, (h) putting down the injection device, (i) picking up and dropping the injection device, (j ) Remove injection device from additional module. The drop in force of the measured axial force when removing or lifting the injection device from the injection site (event f) is more continuous than during piercing (event d) and follows the relaxing needle protection sleeve spring, possibly with the formation of a peak superimposed on the flank caused by a movement of a needle protection sleeve locking mechanism.

States, processes and events in the injection device and during the injection process can be identified by combinatorially linking the information from the force sensor and the microphone, as follows. To detect a start click, the combination of a clear acoustic peak and an increase in force (with remaining on the force plateau) is required. To detect a final click, the combination of a clear acoustic peak and a consistently high force is required. The removal of the injection device and additional module from the injection site is detected by the drop in force after the final click. If the injection device is removed from the injection site before the final click or during the required holding time, this can be detected by the premature drop in force.

Fig.5 shows a diagram for an evaluation electronics as part of the evaluation unit, applicable to an input signal A measured by the force sensor. In a high-pass filter with a cutoff frequency of 200 Hz ( Fig.5 , left), the low-frequency signal components are filtered out. The filtered signal includes both positive and negative deflections, corresponding to the deviations in the force impulse signal compared to a holding force plateau. To avoid negative voltage values, the output signal of the filter is increased to an offset of 2V (half the supply voltage). The resulting signal B is passed to a comparator ( Fig.5 , right), which compares the analog signal with an upper and a lower limit of an amplitude window and converts it into pulses. If the signal prepared in this way exceeds the upper limit value, a first comparator output value C, for example a pulse of plus 1 V, is output or a corresponding bit or character is set. If the signal falls below the lower limit, a second comparator output value D, for example a pulse of minus 1 V, is generated. As a result, a three-valued discrete event pattern is generated as a sequence of positive and negative pulses lasting different lengths, separated by a neutral or average pulse of any length.

The evaluation electronics can be implemented analog or digital or mixed. For example, the high-pass filtered analog sensor signal is fed to a microprocessor, converted by it into a digital signal and fed to the digital comparator function programmed in the microprocessor's memory. A sampling rate for the digitization of the force impulse signal must be selected according to Nyquist, so for a force impulse signal corresponding to an acoustic clicking noise with a frequency spectrum of up to 5 kHz, sampling every 20 microseconds is appropriate.

Fig.6 shows an input signal A measured by a force sensor at the input of a filter, as well as the filtered signal B generated by filtering the signal A at the input of a comparator. The entire process shown lasts 5 seconds, so the power surge signals at the beginning and at the end of the distribution corresponding to a start-of-injection and an end-of-injection click are only visible as narrow peaks.

Fig.7 shows an example of an event pattern formation for the force impulse signal at the beginning of the distribution in Fig.6 , time-resolved over a duration of 8 milliseconds. The unfiltered signal A and the filtered signal B show correspondingly more structure. By comparing the signal B with a first limit value or threshold value represented by the upper horizontal line G1, a first comparator output signal C is generated with three pulses of different lengths. By comparing the signal B with a second limit value or threshold value represented by the lower horizontal line G2, a second comparator output signal D is generated, here comprising a sequence of four pulses of different lengths. The sequence of the second pulses is shown here with negative values for better readability. The event pattern resulting from the selected force impulse with the two components C and D agrees with the characteristic basic pattern or the signature of a start click, represented by curve E, in that the three pulses of the basic pattern lie completely within pulses of the event pattern in time. Accordingly, the force surge signal is identified as originating from a start click. The determination of the limit values G and des The associated basic pattern E is preferably carried out using an iterative procedure with repeated recording and analysis of force impulses with a known origin. The selected limit values then ideally lead to minimal scatter in the event patterns and thus to high reproducibility. The algorithm presented can successfully identify or exclude previous actions and incorrect manipulations such as picking up the additional module, mounting the additional module, removing the needle guard, turning, dropping, loud ambient noises, and shaking holding as force surges that are not relevant to the injection and do not correspond to any basic signal.

Fig.8 shows an extended medical monitoring system with an injection device 1, an additional module 2, a mobile display and output device 31 which can communicate wirelessly with the additional module, and an optional stationary data processing system or expert system 32 based on de-localized data storage (cloud computing). The additional module wirelessly transmits data from an injection process and/or consolidated injection information to a compatible mobile device, for example a smart mobile phone (smartphone) with a special application, or a correspondingly configured portable computer.

The mobile device must be initially set up and configured, for example by installing an application and registering the user. This can be done using a patient data card, which transfers all relevant data to the mobile device via near-field radio communication (NFC) or optical QR codes. If the mobile device is within range of the additional module, this data transmission can take place in real time during an injection process or only after it has ended. In the former case, the mobile device can give instructions to the user in real time and guide them through the next steps. If necessary, the injection information can also be saved on the additional module and only transferred later in consolidated form. The data received from the mobile device can be supplemented by the user, for example by specifying the injection site, and is passed on to the expert system in an appropriate way. The latter stores the data and provides patients, medical staff and health insurers with targeted information, thereby supporting compliance with a therapy plan by the user of the injection device.

REFERENCE SYMBOL LIST

1

injection device

10

Device housing

10a

Window

11

Needle protection sleeve

12

Needle cap remover

13a

Injection

13b

needle

14

Needle protection sleeve spring

15a, 15b

stop element

16

distribution spring

2

Additional module

20

Module housing

20a

opening

20b, 20c

Housing halves

20d

Module sleeve

21

Handle

21a

Grip limitation

22

Force sensor

23a

Electronics holder

23b

Contact switch

23c

Connection indicator

23d

Status display

23e

microphone

23f

battery

23g

Buzzer

11 p.m

Communication unit

24a

release button

24b

Transmission element

31

Mobile device

32

Data processing system

Claims (9)

1. Injection system having an injection device (1), comprising

   - a needle protection sleeve (11) which is displaceable in a longitudinal direction between a proximal and a distal position;

   - a needle protection sleeve spring (14) which is coupled to the needle protection sleeve (11) and which, after substance delivery has taken place, pushes the needle protection sleeve (11) into the distal position, in which it laterally surrounds or shields the needle, the needle protection sleeve spring (14) being tensioned during a piercing process;
   the injection system further comprising an add-on module (2) for attaching to the injection device (1), having a longitudinal axis, the add-on module (2) comprising

   - a force sensor (22) for measuring a force component, in the direction of the longitudinal axis, that is exerted by the injection device on the attached add-on module during an injection process;

   - an evaluation electronics system for evaluating measurements of the force sensor (22) for the purpose of identifying a process or a state of the injection device (1),

   characterized in that the add-on module (2) is designed to identify a piercing process from an increase in an axial force measured by the force sensor to an at least approximately constant value caused by the compressed needle protection sleeve spring, and

   the add-on module (2) having a sleeve-shaped module housing having a device receptacle for receiving the injection device and a handle (21) for holding the injection device and the attached add-on module, a clear width of the device receptacle in the region of the handle being greater than an outer diameter of the injection device (1), so that, at maximum grip pressure, the device receptacle is not pressed onto the injection device and no friction or retaining forces can be transmitted in the longitudinal direction via the device receptacle between the injection device (1) and the add-on module (2) while bypassing the force sensor (22).
2. Injection system according to claim 1, characterized in that the device receptacle at least partially surrounds the injection device in the attached state, the handle surrounding the device receptacle and having an extension of at least half a hand width of a user in the direction of the longitudinal axis.
3. Injection system according to claim 2, characterized in that the add-on module has a holding mechanism which secures the injection device in the direction of the longitudinal axis in the attached state.
4. Injection system according to any of claims 1 to 3, characterized in that the evaluation electronics system is designed to identify a movement of a stop element (15a, 15b) of the injection device, in particular a stop movement of the stop element which signals the start or the end of a discharge.
5. Injection system according to claim 4, characterized in that the evaluation electronics system is designed to generate a multivalent event pattern from a measured force impact signal and to compare the generated multivalent event pattern with a base pattern.
6. Injection system according to any of claims 1 to 3, characterized in that the add-on module has a microphone (23e) for measuring an acoustic signal of the injection process, and in that the evaluation electronics system is designed to identify, on the basis of measurements of the microphone, a movement of a stop element of the injection device which signals the start or the end of a discharge.
7. Injection system according to any of claims 1 to 3, characterized in that the add-on module has an acceleration sensor, the evaluation electronics system being designed to conjointly evaluate measurements from the acceleration sensor and from the force sensor for event identification.
8. Injection system according to any of the preceding claims,
   characterized in that the add-on module comprises a wireless communication unit (23h) for communicating with a mobile device, and/or a status display (23d) for displaying a state of the injection device.
9. Injection system according to any of the preceding claims, the needle protection sleeve spring accelerating a stop element at the end of the discharge, characterized in that the add-on module is designed to identify a stop of the accelerated stop element from a force impact detected by the force sensor.

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